Applications of a Decomposed Analysis Procedure for Area-Array Packages

The goals of the present paper are to apply the recently developed decomposed analysis procedure using a computer code developed in this study. The decomposed technique enables one to determine the equilibrium configuration of electronic packages with significant computational efficiency at a reasonable accuracy. Further, it allows the independent analysis of the subsystems enabling “reusable” modules in a manner analogous to the object-oriented programming paradigm of modern computer languages. The code described here uses a nonlinear optimization procedure that ensures the approximate satisfaction of the balance of mechanical energy. The developed procedure is demonstrated on a variety of two- and three-dimensional hypothetical and “real-world” electronic packages. It is shown that with the use of the decomposed solution methodology, for a 225 I/O PBGA package, a speedup of nearly seven times is achieved at an accuracy loss in displacements of approximately 5.5 percent. It is also shown that the calculated peak shear displacements agree very well with experimental measurements made using laser moire´ interferometry. Since the analysis procedure is independent of the number of solder interconnects, significantly larger time savings are expected for larger packages.